Subxiphoid approach for extracting a giant solitary fibrous tumour of the pleura.

We describe a case of resection of a solitary fibrous tumour of the pleura using video-assisted thoracic surgery and removal of the giant tumour using a subxiphoid incision without the need for minithoracotomy. Use of the subxiphoid approach as a retrieval port is simple and feasible.

Prognostic value of severity indicators of nursing-home-acquired pneumonia versus community-acquired pneumonia in elderly patients.

BACKGROUND: The credibility of prognostic indicators in nursing-home-acquired pneumonia (NHAP) is not clear. We previously reported a simple prognostic indicator in community-acquired pneumonia (CAP): blood urea nitrogen to serum albumin (B/A) ratio. This retrospective study investigated the prognostic value of severity indicators in NHAP versus CAP in elderly patients. METHODS: Patients aged ≥65 years and hospitalized because of NHAP or CAP within the previous 3 years were enrolled. Demographics, coexisting illnesses, laboratory and microbiological findings, and severity scores (confusion, urea, respiratory rate, blood pressure, and age ≥65 [CURB-65] scale; age, dehydration, respiratory failure, orientation disturbance, and pressure [A-DROP] scale; and pneumonia severity index [PSI]) were retrieved from medical records. The primary outcome was mortality within 28 days of admission. RESULTS: In total, 138 NHAP and 307 CAP patients were enrolled. Mortality was higher in NHAP (18.1%) than in CAP (4.6%) (P<0.001). Patients with NHAP were older and had lower functional status and a higher rate of do-not-resuscitate orders, heart failure, and cerebrovascular diseases. The NHAP patients more frequently had typical bacterial pathogens. Using the receiver-operating characteristics curve for predicting mortality, the area under the curve in NHAP was 0.70 for the A-DROP scale, 0.69 for the CURB-65 scale, 0.67 for the PSI class, and 0.65 for the B/A ratio. The area under the curve in CAP was 0.73 for the A-DROP scale, 0.76 for the CURB-65 scale, 0.81 for the PSI class, and 0.83 for the B/A ratio. CONCLUSION: Patient mortality was greater in NHAP than in CAP. Patient characteristics, coexisting illnesses, and detected pathogens differed greatly between NHAP and CAP. The existing severity indicators had less prognostic value for NHAP than for CAP.

Predictive values of semi-quantitative procalcitonin test and common biomarkers for the clinical outcomes of community-acquired pneumonia.

BACKGROUND: The semi-quantitative serum procalcitonin test (Brahms PCT-Q) is available conveniently in clinical practice. However, there are few data on the relationship between results for this semi-quantitative procalcitonin test and clinical outcomes of community-acquired pneumonia (CAP). We investigated the usefulness of this procalcitonin test for predicting the clinical outcomes of CAP in comparison with severity scoring systems and the blood urea nitrogen/serum albumin (B/A) ratio, which has been reported to be a simple but reliable prognostic indicator in our prior CAP study. METHODS: This retrospective study included data from subjects who were hospitalized for CAP from August 2010 through October 2012 and who were administered the semi-quantitative serum procalcitonin test on admission. The demographic characteristics; laboratory biomarkers; microbiological test results; Pneumonia Severity Index scores; confusion, urea nitrogen, breathing frequency, blood pressure, ≥ 65 years of age (CURB-65) scale scores; and age, dehydration, respiratory failure, orientation disturbance, pressure (A-DROP) scale scores on hospital admission were retrieved from their medical charts. The outcomes were mortality within 28 days of hospital admission and the need for intensive care. RESULTS: Of the 213 subjects with CAP who were enrolled in the study, 20 died within 28 days of hospital admission, and 32 required intensive care. Mortality did not differ significantly among subjects with different semi-quantitative serum procalcitonin levels; however, subjects with serum procalcitonin levels ≥ 10.0 ng/mL were more likely to require intensive care than those with lower levels (P < .001). The elevation of semi-quantitative serum procalcitonin levels was more frequently observed in subjects with proven etiology, especially pneumococcal pneumonia. Using the receiver operating characteristic curves for mortality, the area under the curve was 0.86 for Pneumonia Severity Index class, 0.81 for B/A ratio, 0.81 for A-DROP, 0.80 for CURB-65, and 0.57 for semi-quantitative procalcitonin test. CONCLUSIONS: The semi-quantitative serum procalcitonin level on hospital admission was less predictive of mortality from CAP compared with the B/A ratio. However, the subjects with serum procalcitonin levels ≥ 10.0 ng/mL were more likely to require intensive care than those with lower levels.

Impact and indication of early systemic corticosteroids for very severe community-acquired pneumonia.

BACKGROUND: The efficacy of systemic corticosteroids in community-acquired pneumonia (CAP) has not yet been confirmed. We prospectively investigated the clinical features of patients treated with early adjunctive systemic corticosteroids and its clinical impact in very severe CAP. METHODS: One hundred and one consecutive CAP patients having a pneumonia severity index of >130 points were enrolled from August 2010 through February 2013. Early adjunctive systemic corticosteroids were defined as administration of systemic corticosteroids equivalent to prednisone of ≥20 mg/day added to initial antibiotics. The multivariate analysis was performed to evaluate the independent factors associated with mortality. RESULTS: Thirty-two patients (31.7%) died within 28 days of admission. Early adjunctive systemic corticosteroids were administered in 30 patients (29.7%), who more frequently had alteration of mental status, serious respiratory failure, or underlying lung diseases and received fluoroquinolones as initial antibiotics. In most patients treated with early adjunctive systemic corticosteroids, the dosage was less than 60 mg/day of an equivalent to prednisone by bolus intravenous infusion for a period shorter than 8 days. The occurrence of adverse events did not differ between the groups. Factors independently associated with mortality were blood urea nitrogen (hazard ratio [HR] 1.02, 95% confidence interval [CI] 1.00-1.04), serum albumin (HR 0.44, 95% CI 0.22-0.86), a requirement for intensive care (HR 4.93, 95% CI 1.75-13.87), and the therapy with early adjunctive systemic corticosteroids (HR 0.29, 95% CI 0.11-0.81). CONCLUSION: Early adjunctive systemic corticosteroids may have an effect to reduce the mortality in very severe CAP, although a larger-scale study is necessary.

Blood urea nitrogen to serum albumin ratio independently predicts mortality and severity of community-acquired pneumonia.

BACKGROUND: Early studies of community-acquired pneumonia showed that nonsurvivors had higher blood urea nitrogen levels and lower serum albumin levels than survivors. Therefore, elevation of the blood urea nitrogen to serum albumin (B/A) ratio may identify patients with community-acquired pneumonia who are becoming critically ill. This study investigated the correlation between commonly used laboratory markers, in particular the B/A ratio, and clinical outcomes of community-acquired pneumonia. METHODS: This observational study was performed in consecutive patients with community-acquired pneumonia admitted to our hospital over a period of one year. Blood counts, commonly used laboratory markers, microbiological tests, and calculation of Pneumonia Severity Index (PSI) and CURB-65 were done on admission. The endpoints were mortality within 28 days of admission and requirement for intensive care. RESULTS: One hundred and seventy-five patients with community-acquired pneumonia were enrolled. Nineteen patients died within 28 days of admission and 29 patients required intensive care. Using multivariate analysis, independent factors associated with mortality were the requirement for intensive care (odds ratio [OR] 14.96, 95% confidence interval [CI] 3.73-60.03, P < 0.001), PSI class (OR 3.55, 95% CI 1.08-11.66, P = 0.037), and B/A ratio (OR 1.10, 95% CI 1.01-1.20, P = 0.037). Similarly, independent factors associated with need for intensive care were PSI class (OR 5.35, 95% CI 1.90-15.06, P = 0.002), CURB-65 (OR 2.37, 95% CI 1.26-4.45, P = 0.007), and B/A ratio (OR 1.27, 95% CI 1.09-1.47, P = 0.002). CONCLUSION: The B/A ratio is a simple but independent predictor of mortality and severity of community-acquired pneumonia.

Soluble Fas and Fas ligand provide new information on metastasis and response to chemotherapy in SCLC patients.

BACKGROUND: The Fas/Fas ligand (FasL) system is a major regulator of apoptosis. Chemotherapeutic drugs have been shown to induce Fas expression on the surface of lung cancer cells, and cancer cell apoptosis. However, this mechanism is not considered to be associated with Fas expressed on lung cancer cells. Soluble Fas and FasL concentrations are reportedly elevated in the peripheral blood of patients with lung cancer, but the roles of circulating soluble Fas and FasL in that disease have not been clarified. MATERIALS AND METHODS: We measured the circulating soluble Fas and FasL levels in 21 patients with small cell lung cancer (SCLC), and 12 healthy matched controls, in order to examine whether such ligands could provide any important information and/or reveal any new clinical features of SCLC. RESULTS: In the CR patients, the neuronal specific enolase (NSE), soluble Fas and soluble FasL concentrations were 21.26+/-3.65 ng/ml, 3.58+/-0.19 ng/ml and 0.50+/-0.15 ng/ml, while in the partial response (PR)/no change (NC)/progressive disease (PD) group of patients they were 33.96+/-7.86 ng/ml, 5.29+/-0.29 ng/ml and 0.59+/-0.07 ng/ml, respectively. The NSE, soluble Fas and soluble FasL concentrations were all elevated in the PR/NC/PD patients, however, significant differences were only seen in Fas concentration between CR and PR/NC/PD patients and CR patients and the controls (p<0.001). CONCLUSIONS: Serum soluble Fas and FasL play important roles in the proliferation and metastasis of SCLC, as well as in the cytotoxic reaction and apoptosis induced by anticancer drugs in SCLC. Further study of the mechanisms and participation of circulating soluble Fas and FasL is necessary to develop treatment strategies for SCLC.

HHV-6 and 7 DNA loads in lung tissues collected from patients with interstitial pneumonia.

The aim of this study is to determine whether human herpesvirus 6 (HHV-6) and HHV-7 might play an important role in causing interstitial pneumonia in patients who have not undergone transplantation. HHV-6 and HHV-7 DNAs were quantitated by real-time polymerase chain reaction (PCR) in paraffin embedded lung tissues collected from 24 patients having the disease. Control tissues (without fibrosis) were also collected from 19 of the 24 patients. Statistical analysis was carried out by the Wilcoxon signed rank test or the Mann-Whitney U-test. HHV-6 DNA was detected in 3 (12.5%) of the 24 target tissues and 3 (15.8%) of the 19 control tissues, respectively. In contrast, HHV-7 DNA was detected in 19 (79.2%) of the 24 target tissues and 11 (57.9%) of the 19 control tissues. Neither HHV-6 DNA load (P = 0.6395) nor HHV-7 DNA load (P = 0.5966) in target tissues differed between males and females. Neither HHV-6 DNA load (P = 0.9589) nor HHV-7 DNA load (P = 0.7419) in target tissues differed between cases with and without underlying collagen disease. While HHV-6 DNA load did not differ between the target and control tissues (P > 0.9999), the HHV-7 DNA load was significantly higher in the target tissue than in the control tissue (P = 0.0298). This study suggests that HHV-7 may play an important role in causing interstitial pneumonia in patients who are not transplant recipients.

[A case of Q fever infection causing acute exacerbation of chronic respiratory failure].

The authors report a case of Q fever infection that caused acute exacerbation of chronic respiratory failure, which had developed as a sequela of pulmonary tuberculosis. This case was found on wide-ranging serological screening for respiratory infection performed in order to investigate the prevalence of Q fever in Japan. A 73-year-old man who had been treated for hypertension and sequelae of pulmonary tuberculosis was admitted to our hospital because of fever, productive cough, and dyspnea on effort. Hypoxia and right heart failure were detected on arterial blood analysis and ultrasonography. The acute exacerbation was triggered by respiratory infection and although the infection improved on azithromycin treatment after admission, respiratory failure continued for the period of admission. Home oxygen therapy was required for the management of chronic respiratory failure on discharge. Paired serum samples were tested for antibodies against Coxiella burnetii by indirect immunofluorescence, showing an elevated antibody titer in the convalescent phase. We believe that Q fever infection caused acute exacerbation of chronic respiratory failure, and that C. burnetii is an agent that might influence the clinical course of chronic respiratory failure.

Role of lysophosphatidylcholine in eosinophil infiltration and resistance in airways.

1. Lysophosphatidylcholine (Lyso-PC), which is synthesized by phospholipase A2, is generally considered to induce adhesion molecules. However, little is known about the involvement of Lyso-PC in the pathogenesis of bronchial asthma. The present study was designed to examine whether pre-exposure to Lyso-PC causes eosinophil recruitment and an increase in resistance in airways. 2. Eosinophils in bronchoalveolar lavage fluid (BALF) and the airway walls were enumerated after inhalation of 0.5 mg/mL Lyso-PC to guinea-pigs for 10 min. Respiratory resistance (Rrs) was recorded continuously over 6 h after inhalation of an equi-dose of Lyso-PC for an equivalent period. 3. The proportion of eosinophils was increased from 10.7 +/- 3.3 to 27.5 +/- 3.1% (P < 0.0001) in BALF 6 h after inhalation of Lyso-PC, whereas the proportion of neutrophils and lymphocytes was not increased. Histological examination also showed uniform distribution of eosinophils in the airway wall of bronchi and bronchioles 6 h after inhalation of Lyso-PC. The number of eosinophils (/10 h.p.f.) in the bronchi and bronchioles was increased from 43.5 +/- 16.8 to 154.8 +/- 21.7 (P < 0.0001) and from 34.8 +/- 0.7 to 106.0 +/- 26.6 (P < 0.01), respectively. This eosinophil infiltration was similarly observed 24 h later. 4. Next, we examined the effects of eosinophil infiltration induced by Lyso-PC on Rrs. Inhalation of Lyso-PC caused a slow increase in Rrs and the percentage increase in Rrs was 19.8 +/- 1.9% (P < 0.0001) 6 h later. Eosinophil infiltration and an increase in Rrs did not occur after inhalation of physiological saline. These phenomena induced by Lyso-PC were diminished by pretreatment with dexamethasone (6 micro g/kg per day for 3 days). 5. Lysophosphatidylcholine causes eosinophil infiltration and a subsequent increase in resistance in airways. Our results indicate that Lyso-PC may be involved in the pathophysiology of bronchial asthma.

The function of GADD34 is a recovery from a shutoff of protein synthesis induced by ER stress: elucidation by GADD34-deficient mice.

GADD34 is a protein that is induced by stresses such as DNA damage. The function of mammalian GADD34 has been proposed by in vitro transfection, but its function in vivo has not yet been elucidated. Here we generated and analyzed GADD34 knockout mice. Despite their embryonic stage- and tissue-specific expressions, GADD34 knockout mice showed no abnormalities at fetal development and in early adult life. However, in GADD34-/- mouse embryonic fibroblasts (MEFs), recovery from a shutoff of protein synthesis was delayed when MEFs were exposed to endoplasmic reticulum (ER) stress. The phosphorylation of eukaryotic translation initiation factor 2 alpha (eIF2alpha) at Ser51 induced by thapsigargin or DTT was prolonged in GADD34-/- MEF, although following treatment with tunicamycin, the eIF2alpha phosphorylation level did not change in either GADD34+/+ or GADD34-/- cells. ER stress stimuli induced expressions of Bip (binding Ig protein) and CHOP (C/EBP homologous protein) in MEF of wild-type mice. These expressions were strongly reduced in GADD34-/- MEF, which suggests that GADD34 up-regulates Bip and CHOP. These results indicate that GADD34 works as a sensor of ER stress stimuli and recovers cells from shutoff of protein synthesis.

Asthma health status: influence of disease severity categorized by peak expiratory flow.

To evaluate the health status of patients with stable asthma and determine how disease severity affects the status, 68 consecutive patients were recruited from an outpatient clinic at an university hospital. Health status was assessed with the St. George's Respiratory Questionnaire and the Asthma Quality of Life Questionnaire (AQLQ). The results of the questionnaires revealed that the mean % predicted peak expiratory flow (PEF) in the preceding 2 weeks correlated most significantly with each total score for the two health status measures. We also found that, in the groups classified by mean % predicted PEF (mild, PEF > or = 80%; moderate, 60 to 79%; severe, < 60%), there were significant differences in all SGRQ scores (p < 0.05). In a subgroup analysis, the scores for moderate and severe patients were significantly worse than for mild patients in all four components (p < 0.05). Almost the same tendency was observed in the score distribution on the AQLQ. We conclude that mean % predicted PEF correlated most with the health status of the patients. Patients with PEF higher than 80% of predicted value generally maintained a better health status than did those with less than 80% of predicted PEF. Achieving higher than 80% of predicted PEF is important in managing asthma from the viewpoint of health status.

Slow deactivation and U-shaped inactivation properties in cloned Cav1.2b channels in Chinese hamster ovary cells.

Whole-cell patch-clamp techniques were applied to Chinese hamster ovary cells stably expressing cloned smooth muscle Ca(2+) channel alpha(1)-subunits. In the presence of Ba(2+) as a charge carrier, U-shaped inactivation was observed in the presence and absence of Ca(2+) agonists. Also, tail currents deactivated slowly when conditioning steps of positive potential were applied. The deactivation time constant was decreased by hyperpolarizing the repolarization step. Application of ATP-gamma-S or H-7 had little effect on the conditions necessary to induce slow tail, suggesting involvement of physical processes in the channel protein. In the presence of Bay K 8644, additional application of nifedipine decreased the amplitudes of the test and tail currents induced by a test step preceded by a conditioning step to +80 mV, but did not affect the decay time constant of the tail current. From these results and assumptions we have drawn up a kinetic scheme with one closed state, two open states (O(1), O(2)) and two inactivated states linked to the closed state and open state O(1), respectively, i.e., open state O(2) protected from inactivation. Computer calculation reconstructed slow deactivation and U-shaped inactivation properties. A similar kinetic scheme with Ca(2+)-agonist-binding states accounted for the results in the presence of Ca(2+) agonists.

Effects of direct and indirect activation of G protein of adenylyl cyclase on the subsequent response to beta-adrenergic receptor agonists in human trachealis.

To examine the response to beta-adrenergic receptor agonists (beta-agonists) following prolonged activation of the stimulatory G protein of adenylyl cyclase (Gs), relaxation by isoproterenol (isoprenaline, CAS 949-36-0) and formoterol (CAS 73573-87-2), a long-acting beta-agonist, after exposure to formoterol was measured in human tracheal smooth muscle, using isometric tension records. Prior exposure to formoterol (0.3-30 nmol/l) for 45 min reduced the subsequent relaxation induced by this drug in a concentration-dependent manner, but only modestly reduced that induced by isoproterenol. Next, the effects of cholera toxin (CTX, CAS 9012-63-9) an irreversible direct activator of Gs and formoterol on the reduced responsiveness to isoproterenol after continuous and repeated exposure to isoprotenerol were examined. Preincubation with cholera toxin (0.02-2 micrograms/ml) caused concentration-dependent inhibition of the desensitization induced by isoproterenol, but preincubation with formoterol did not. These results indicate that prolonged activation of Gs via beta-adrenergic receptors does not cause cross-desensitization to short-acting beta-agonists. However, it also fails to inhibit the desensitization of beta-adrenergic receptors after excessive exposure to short-acting beta-agonists. Activation of Gs via a pathway that bypasses the receptors may be beneficial for the prevention of this phenomenon.

Trends in asthma mortality in Japan.

Asthma mortality has been increasing in many developed countries in recent years, so we have described the epidemiological features of asthma in Japan. Data on all certified asthma deaths from 1950 to 1997 were obtained from The National Vital Statistics, published annually by the Ministry of Health and Welfare. Trends in crude and age-adjusted asthma mortality rates, as well as age-specific mortality rates, were analyzed. Age and birth cohort effects on mortality rates were also examined using multiplicative models. Between 1950 and 1980, crude asthma mortality rates steadily decreased in both sexes and began to level off thereafter. Age-adjusted mortality rates have also decreased since 1950, and showed a persistent downward trend in both sexes even in recent years. Asthma mortality rates were higher in males than in females during the entire study period. When analysis was restricted to those aged 5 to 34 years, an upward trend since 1980 was observed. The multiplicative model showed a rapidly decreasing cohort effect on mortality among those born after 1860. However, the slope increased in the cohorts born after 1950 in both sexes. The age effect increased linearly with advancing age after 50 years in both sexes. Overall asthma mortality rates have been decreasing during the past five decades in Japan, but the mortality rate has increased among the 5-34-year-old age group since 1980. The high fatality rate stemming from the overuse of beta 2-agonists may account for the mortality increase.

Bioelectric toxicity caused by chlorpromazine in human lung epithelial cells.

Endogeneous and exogeneous amine-containing substances possess pneumophilic properties. Among them, tricyclic amphiphilic amine drugs like neuroleptics intensively accumulate in the lung cell membrane and occasionally cause severe respiratory disorders. In the present study, we examined the bioelectric toxicity of chlorpromazine (CPZ), a commonly used neuroleptic, in human lung epithelial cells. CPZ concentration-dependently inhibited the isoproterenol (ISO)-generated short-circuit current (I(sc)) sensitive to a nonselective K(+) channel blocker, clotrimazole (30 microM), but insensitive to a selective Ca(2+)-activated K(+) (K(Ca)) channel blocker, charybdotoxin (ChTx, 100 nM). The effects of apical CPZ on the ISO-induced responses were greater than those of basolateral CPZ. Forskolin- and 8-bromo-cyclic AMP-induced I(sc) were partially prevented by CPZ. Nystatin permeabilization of the monolayers revealed that CPZ attenuated the basolateral K(+) current elicited by ISO more than that elicited by forskolin and that the apical Cl(-) current elicited by forskolin was instead potentiated by CPZ, although it inhibited the ISO-induced Cl(-) current. 1-Ethyl-2-benzimdazolinone (1-EBIO, a K(Ca) channel opener, 500 microM)- and ionomycin (Ca(2+) ionophore, 1 microM)-evoked Cl(-) secretions were also sensitive to CPZ. These results indicate that CPZ inhibits transepithelial Cl(-) transport, affecting at least two different targets: the beta-adrenergic receptor and the basolateral K(+) channels (especially the K(Ca) channel). Electrostatic interactions at the inner surface of the membrane between the protonated amines of CPZ and negatively charged portions of the plasma membrane may be involved in the mechanisms.

Effects of sustained-release tulobuterol on asthma control and beta-adrenoceptor function.

1. Recently, a patch formulation of tulobuterol, a beta-adrenoceptor (AR) agonist, has been developed using a transdermal delivery system. The present study was designed to determine whether beta-AR function and asthma control were affected by the sustained-released beta-AR agonist. 2. Tulobuterol (2 mg) was applied daily for 8 weeks to seven patients with bronchial asthma in whom the morning dip in the peak expiratory flow (PEF) rate developed even though inhaled glucocorticoids were being taken. After treatment with tulobuterol, the early morning reduction in PEF was suppressed and PEF values were increased from 367 +/- 35 to 439 +/- 38 L/min (P < 0.05). The rescue use of inhaled beta-AR agonists was decreased from 6.9 +/- 2.0 to 1.0 +/- 0.7 puffs/week (P < 0.01). Symptom scores also decreased from 8.3 +/- 3.4 to 2.1 +/- 1.4 score/week (P < 0.01). 3. Next, we sought to examine the effects of exposure to tulobuterol on beta-AR function in guinea-pig tracheal smooth muscle. After exposure of tissues to tulobuterol (0.01-10 micro mol/L) for 45 min, the inhibitory effects of tulobuterol on methacholine-induced contractions were attenuated in a concentration-dependent manner. However, the inhibitory effects of tulobuterol were not affected after exposure to 0.01 micro mol/L tulobuterol (a concentration greater than serum levels in clinical use). In contrast, the inhibitory effects of procaterol were not affected after exposure to tulobuterol under the same experimental conditions. 4. These results indicate that the combination of sustained-released tulobuterol with inhaled glucocorticoid therapy is beneficial to patients with bronchial asthma who suffer from symptoms induced by the morning dip in PEF. Moreover, chronic exposure to lower concentrations of tulobuterol does not lead to desensitization of beta-AR in airway smooth muscle.

Different effects of beta-adrenoceptor desensitization on inhibitory actions in guinea-pig trachealis.

1. To determine the inhibitory effects of agents that pass through and bypass beta-adrenoceptors under conditions of tolerance to beta-adrenoceptor agonists, we examined the inhibition by the beta-adrenoceptor agonists forskolin and theophylline against contraction induced by methacholine (MCh) after exposure to higher concentrations of a beta-adrenoceptor agonist for a long time in guinea-pig tracheal smooth muscle, using isometric tension records. 2. After exposure to procaterol (0.0003-3 micromol/L) for 45 min, the inhibitory effect of 0.03 micromol/L procaterol on 1 micromol/L MCh-induced contraction was attenuated in a concentration-dependent manner, whereas after exposure to isoprenaline (0.0003-3 micromol/L) for an equivalent time, the inhibitory effect of isoprenaline was markedly attenuated at each concentration. However, after exposure to 3 micromol/L procaterol for 45 min, the inhibitory actions of forskolin and theophylline were, conversely, augmented. 3. These phenomena were observed under conditions whereby the response to MCh returned to control levels 6 h after removal of 3 micromol/L procaterol. The percentage inhibition produced by 0.1 micromol/L forskolin against 1 micromol/L MCh after exposure to normal bathing solution or 3 micromol/L procaterol for 45 min was 9.8 +/- 5.5 and 82.8 +/- 6.5%, respectively (P < 0.001). These values for 100 micromol/L (18 microg/mL) theophylline on MCh resposnes were 9.9 +/- 8.5 and 88.0 +/- 4.4% (n = 6 for both), respectively (P < 0.001). 4. The inhibitory action of agents that bypass beta-adrenoceptors was markedly augmented under conditions of beta-adrenoceptor desensitization in airway smooth muscle. 5. In conclusion, procaterol is less potent in causing desensitization of beta-adrenoceptors than isoprenaline. The activity of adenylyl cyclase may be enhanced after exposure to a high concentration of beta-adrenoceptor agonists.

Bisphenol A inhibits Cl(-) secretion by inhibition of basolateral K+ conductance in human airway epithelial cells.

There has been growing concern about the potential threat of hormone-disrupting chemicals like bisphenol A to various aspects of animal and human health. We studied the effects of bisphenol A on the Cl(-) secretion in human airway epithelial Calu-3 cells. Pretreatment with bisphenol A (IC(50) = 60 microM, for 30 min) prevented isoproterenol (10 nM)-generated short-circuit current (I(sc)) more potently than 17beta-estradiol or tamoxifen (IC(50) = 1 mM). 5'-Nitro-2-(3-phenylpropylamino) benzoate-sensitive apical conductance potentiated by isoproterenol was not affected by the pretreatment with either of these estrogenic compounds. The effects of bisphenol A were simulated in I(sc) responses to forskolin (10 microM) and 8-bromo-cAMP (1 mM). Nystatin permeabilization of Calu-3 monolayers revealed that bisphenol A attenuated 8-bromo-cAMP-induced basolateral K+ current, which is sensitive to clotrimazole (30 microM) and insensitive to charybdotoxin (100 nM), without affecting the apical Cl(-) current. Bisphenol A, but neither 17beta-estradiol nor tamoxifen, interrupted the charybdotoxin-sensitive component of I(sc) stimulated by 1-ethyl-2-benzimidazolinone (1-EBIO; 500 microM). The inhibitory effects of bisphenol A on these Cl(-) secretory stimuli were remarkable when applied to the apical rather than the basolateral membrane. Alternatively, long-term incubation of bisphenol A (1 microM; 12-72 h) had no discernible effect on isoproterenol- and 1-EBIO-induced Cl(-) secretion. These findings indicate that short-term exposure to bisphenol A attenuates transepithelial Cl(-) secretion through inhibition of both cAMP- and Ca(2+)-activated K+ channels on the basolateral membrane, interacting from the cytosolic surface in Calu-3 cells.

Regulation of capacitative and noncapacitative receptor-operated Ca2+ entry by rho-kinase in tracheal smooth muscle.

To determine the mechanisms of Ca2+ mobilization induced by receptor agonists, we examined the role of Rho-kinase on the sarcoplasmic reticulum (SR) Ca2+ stores-dependent and -independent Ca2+ influx in guinea pig tracheal smooth muscle (TSM). Isometric tension and intracellular Ca2+ concentration ([Ca2+]i) were simultaneously measured using fura-2-loaded tissues. Depletion of the SR Ca2+ stores by thapsigargin caused an increase in [Ca2+]i and contraction, demonstrating capacitative Ca2+ entry (CCE). Because CCE was not inhibited by nifedipine, voltage-operated Ca2+ channels are not involved in CCE. Under the condition that CCE is fully activated, methacholine (MCh) and histamine caused further increases in [Ca2+]i and tension, demonstrating noncapacitative receptor-operated Ca2+ entry (non-CCE). The Ca2+ influx and contraction via non-CCE was inhibited by Y-27632, a Rho-kinase inhibitor, in a concentration-dependent fashion. In contrast, Y-27632 did not affect thapsigargin-induced CCE. Cytochalasin D, which disrupts actin cytoskeleton, inhibited contraction induced by CCE or MCh with no change in [Ca2+]i. Our results indicate that not only CCE but also non-CCE exist in TSM and that the latter is regulated by Rho-kinase, independent of actin cytoskeleton. In conclusion, Ca2+ influx regulated by the RhoA/Rho-kinase pathway may play a functional role in contraction by agonists.